How should i win her back!? i really love her?

She dumped me yesterday and all i got out of her was something about she didn't like the "forever" stuff. i said corny romantic things cause she loves romance movies books and shows and she was worried that i didn't like her a week ago. She wants to be friends but she avoided me all day and sometimes in cl she would look back at me discreetly but if i acted like i noticed shed turn away. shes loved me for 3 years before we dated and i dont see wat happened everything was goin great. should i run to her and confess undying love or leave her alone?